From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [PATCH 11/11] ARM: tegra: pcie: Add device tree support Date: Fri, 09 Mar 2012 09:47:11 -0700 Message-ID: <4F5A340F.6080303@wwwdotorg.org> References: <1331218291-16119-1-git-send-email-thierry.reding@avionic-design.de> <1331218291-16119-12-git-send-email-thierry.reding@avionic-design.de> <4F59253D.7070100@wwwdotorg.org> <20120309063115.GA25208@avionic-0098.mockup.avionic-design.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120309063115.GA25208-RM9K5IK7kjIQXX3q8xo1gnVAuStQJXxyR5q1nwbD4aMs9pC9oP6+/A@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Thierry Reding Cc: Liam Girdwood , Mark Brown , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jesse Barnes , linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Grant Likely , Rob Herring , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Russell King , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Colin Cross , Olof Johansson List-Id: linux-tegra@vger.kernel.org On 03/08/2012 11:31 PM, Thierry Reding wrote: > * Stephen Warren wrote: >> On 03/08/2012 07:51 AM, Thierry Reding wrote: >>> This commit adds support for instantiating the Tegra PCIe controller >>> from a device tree. >>> >>> Signed-off-by: Thierry Reding >> >>> diff --git a/Documentation/devicetree/bindings/pci/tegra-pcie.txt b/Documentation/devicetree/bindings/pci/tegra-pcie.txt >> >>> +NVIDIA Tegra PCIe controller >>> + >>> +Required properties: >>> +- compatible: "nvidia,tegra20-pcie" >>> +- reg: physical base address and length of the controller's registers >>> +- interrupts: the interrupt outputs of the controller >>> + >>> +Optional properties: >>> +- pex-clk-supply: supply voltage for internal reference clock >>> +- vdd-supply: power supply for controller (1.05V) >> >> Mark, Liam, >> >> Should those *-supply properties really be optional? I got the >> impression talking to Mark in a different thread that all regulators >> should exist, although their implementation may be via a fixed >> regulator, with no GPIO, as determined by the board design. > > If I read the TrimSlice code correctly, there is no regulator setup required > to make PCIe work there presumably because they hardwire the proper voltages. Yes. I believe that's exactly what the fixed regulator is for. > On the other hand, maybe a better solution in this case would be to use the > dummy regulator in those cases. Mark indicated dummy regulators weren't the preferred mechanism: http://lkml.org/lkml/2012/2/25/30